Add support for @catch on fragments/queries/mutations and aliased inl…

…ine fragments (#4838)

Summary:
`catch` was originally conceived as a means for handling field errors, so we built it as a directive on fields. However, as the design evolved we opted to make it additionally catch any errors nested within it. With this newer approach, there’s no reason to limit `catch` to just fields. Any GraphQL construct which gets read as a concrete value should be able to operate as a `catch` boundary.

This PR adds support for marking fields/queries/mutations and aliased fragments as `catch` boundaries. This means:

1. Their value will be read out as either nullable or a `Result` type
2. `semanticNonNull` values nested within the fragment/operation/mutation/aliased fragment will be typed using their semantic type (non-nullable)

One particularly nice thing this enables is that it allows `catch` to act as a non-destructive alternative to `throwOnFieldError`.

## Additional Bug Fixes

Along the way I noticed and fixed a few bugs:

1. Semantic nullability was not respected within inline fragments nested within `catch` or `throwOnFieldError`
2. Errors that bubbled up to a `catch(to: NULL)` directive would not actually cause the value to become null.

Pull Request resolved: #4838

Reviewed By: itamark

Differential Revision: D65432323

Pulled By: captbaritone

fbshipit-source-id: 7fd1313e6d1ae0bda2d6354ef931f10fcfa72e9e

compiler/crates/relay-codegen/src/build_ast.rs

@@ -536,6 +536,12 @@ impl<'schema, 'builder, 'config> CodegenBuilder<'schema, 'builder, 'config> {
                 value: Primitive::Bool(true),
             })
         }
+        if let Some(catch_metadata) = CatchMetadataDirective::find(&fragment.directives) {
+            metadata.push(ObjectEntry {
+                key: CODEGEN_CONSTANTS.catch_to,
+                value: Primitive::String(catch_metadata.to.into()),
+            })
+        }
         if let Some(refetch_metadata) = RefetchableMetadata::find(&fragment.directives) {
             let refetch_connection = if let Some(connection_metadata) = connection_metadata {
                 let metadata = &connection_metadata[0]; // Validated in `transform_refetchable`
@@ -803,7 +809,7 @@ impl<'schema, 'builder, 'config> CodegenBuilder<'schema, 'builder, 'config> {
         if let Some(required_metadata) = RequiredMetadataDirective::find(&field.directives) {
             self.build_required_field(required_metadata, resolver_primitive)
         } else if let Some(catch_metadata) = CatchMetadataDirective::find(&field.directives) {
-            self.build_catch_field(catch_metadata, resolver_primitive)
+            self.build_catch_node(catch_metadata, resolver_primitive)
         } else {
             resolver_primitive
         }
@@ -1031,7 +1037,7 @@ impl<'schema, 'builder, 'config> CodegenBuilder<'schema, 'builder, 'config> {
         }))
     }
 
-    fn build_catch_field(
+    fn build_catch_node(
         &mut self,
         catch_metadata: &CatchMetadataDirective,
         primitive: Primitive,
@@ -1072,7 +1078,7 @@ impl<'schema, 'builder, 'config> CodegenBuilder<'schema, 'builder, 'config> {
         if let Some(required_metadata) = RequiredMetadataDirective::find(&field.directives) {
             self.build_required_field(required_metadata, primitive)
         } else if let Some(catch_metadata) = CatchMetadataDirective::find(&field.directives) {
-            self.build_catch_field(catch_metadata, primitive)
+            self.build_catch_node(catch_metadata, primitive)
         } else {
             primitive
         }
@@ -1172,7 +1178,7 @@ impl<'schema, 'builder, 'config> CodegenBuilder<'schema, 'builder, 'config> {
         if let Some(required_metadata) = RequiredMetadataDirective::find(&field.directives) {
             self.build_required_field(required_metadata, primitive)
         } else if let Some(catch_metadata) = CatchMetadataDirective::find(&field.directives) {
-            self.build_catch_field(catch_metadata, primitive)
+            self.build_catch_node(catch_metadata, primitive)
         } else {
             primitive
         }
@@ -1323,7 +1329,7 @@ impl<'schema, 'builder, 'config> CodegenBuilder<'schema, 'builder, 'config> {
             } else if let Some(catch_metadata) =
                 CatchMetadataDirective::find(&frag_spread.directives)
             {
-                self.build_catch_field(catch_metadata, resolver_primitive)
+                self.build_catch_node(catch_metadata, resolver_primitive)
             } else {
                 resolver_primitive
             }
@@ -1939,7 +1945,7 @@ impl<'schema, 'builder, 'config> CodegenBuilder<'schema, 'builder, 'config> {
         if let Some(required_metadata) = required_metadata {
             self.build_required_field(&required_metadata, field)
         } else if let Some(catch_metadata) = catch_metadata {
-            self.build_catch_field(&catch_metadata, field)
+            self.build_catch_node(&catch_metadata, field)
         } else {
             field
         }
@@ -1997,11 +2003,18 @@ impl<'schema, 'builder, 'config> CodegenBuilder<'schema, 'builder, 'config> {
                         type_: Primitive::SkippableNull,
                         abstract_key: Primitive::SkippableNull,
                     }));
-                    Primitive::Key(self.object(object! {
+                    let aliased_fragment = Primitive::Key(self.object(object! {
                         fragment: primitive,
                         kind: Primitive::String(CODEGEN_CONSTANTS.aliased_inline_fragment_spread),
                         name: Primitive::String(fragment_alias_metadata.alias.item),
-                    }))
+                    }));
+                    if let Some(catch_metadata) =
+                        CatchMetadataDirective::find(&inline_frag.directives)
+                    {
+                        self.build_catch_node(catch_metadata, aliased_fragment)
+                    } else {
+                        aliased_fragment
+                    }
                 } else {
                     // TODO(T63559346): Handle anonymous inline fragments with no directives
                     panic!(
@@ -2080,11 +2093,18 @@ impl<'schema, 'builder, 'config> CodegenBuilder<'schema, 'builder, 'config> {
                 if let Some(fragment_alias_metadata) =
                     FragmentAliasMetadata::find(&inline_frag.directives)
                 {
-                    Primitive::Key(self.object(object! {
+                    let aliased_fragment = Primitive::Key(self.object(object! {
                         fragment: primitive,
                         kind: Primitive::String(CODEGEN_CONSTANTS.aliased_inline_fragment_spread),
                         name: Primitive::String(fragment_alias_metadata.alias.item),
-                    }))
+                    }));
+                    if let Some(catch_metadata) =
+                        CatchMetadataDirective::find(&inline_frag.directives)
+                    {
+                        self.build_catch_node(catch_metadata, aliased_fragment)
+                    } else {
+                        aliased_fragment
+                    }
                 } else {
                     primitive
                 }

compiler/crates/relay-codegen/src/constants.rs

@@ -21,6 +21,7 @@ pub struct CodegenConstants {
     pub backward: StringKey,
     pub cache_id: StringKey,
     pub catch_field: StringKey,
+    pub catch_to: StringKey,
     pub client_abstract_types: StringKey,
     pub client_edge_backing_field_key: StringKey,
     pub client_edge_model_resolvers: StringKey,
@@ -141,6 +142,7 @@ lazy_static! {
         backward: "backward".intern(),
         cache_id: "cacheID".intern(),
         catch_field: "CatchField".intern(),
+        catch_to: "catchTo".intern(),
         client_abstract_types: "clientAbstractTypes".intern(),
         client_edge_backing_field_key: "backingField".intern(),
         client_edge_model_resolvers: "modelResolvers".intern(),

compiler/crates/relay-codegen/tests/catch_directive_codegen.rs

@@ -7,6 +7,7 @@
 
 use std::sync::Arc;
 
+use common::FeatureFlag;
 use common::SourceLocationKey;
 use fixture_tests::Fixture;
 use graphql_ir::build;
@@ -20,6 +21,7 @@ use relay_config::ProjectConfig;
 use relay_test_schema::get_test_schema;
 use relay_test_schema::get_test_schema_with_extensions;
 use relay_transforms::catch_directive;
+use relay_transforms::fragment_alias_directive;
 
 pub async fn transform_fixture(fixture: &Fixture<'_>) -> Result<String, String> {
     let parts: Vec<_> = fixture.content.split("%extensions%").collect();
@@ -34,7 +36,8 @@ pub async fn transform_fixture(fixture: &Fixture<'_>) -> Result<String, String>
         .map_err(|diagnostics| diagnostics_to_sorted_string(fixture.content, &diagnostics))?;
     let program = Program::from_definitions(Arc::clone(&schema), ir);
 
-    catch_directive(&program)
+    fragment_alias_directive(&program, &FeatureFlag::Disabled)
+        .and_then(|next_program| catch_directive(&next_program))
         .map(|next_program| {
             next_program
                 .fragments()

compiler/crates/relay-codegen/tests/catch_directive_codegen/fixtures/catch_directive_aliased_inline_fragment.expected

@@ -0,0 +1,48 @@
+==================================== INPUT ====================================
+fragment MyFragment on Node  {
+  id
+  ... on User @catch(to: RESULT) @alias {
+    name
+  }
+}
+==================================== OUTPUT ===================================
+{
+  "argumentDefinitions": [],
+  "kind": "Fragment",
+  "metadata": null,
+  "name": "MyFragment",
+  "selections": [
+    {
+      "alias": null,
+      "args": null,
+      "kind": "ScalarField",
+      "name": "id",
+      "storageKey": null
+    },
+    {
+      "kind": "CatchField",
+      "field": {
+        "fragment": {
+          "kind": "InlineFragment",
+          "selections": [
+            {
+              "alias": null,
+              "args": null,
+              "kind": "ScalarField",
+              "name": "name",
+              "storageKey": null
+            }
+          ],
+          "type": "User",
+          "abstractKey": null
+        },
+        "kind": "AliasedInlineFragmentSpread",
+        "name": "User"
+      },
+      "to": "RESULT",
+      "path": "User"
+    }
+  ],
+  "type": "Node",
+  "abstractKey": "__isNode"
+}

compiler/crates/relay-codegen/tests/catch_directive_codegen/fixtures/catch_directive_aliased_inline_fragment.graphql

@@ -0,0 +1,6 @@
+fragment MyFragment on Node  {
+  id
+  ... on User @catch(to: RESULT) @alias {
+    name
+  }
+}

compiler/crates/relay-codegen/tests/catch_directive_codegen/fixtures/catch_directive_aliased_inline_fragment_no_condition.expected

@@ -0,0 +1,48 @@
+==================================== INPUT ====================================
+fragment MyFragment on Node  {
+  id
+  ... @catch(to: RESULT) @alias(as: "myAlias") {
+    name
+  }
+}
+==================================== OUTPUT ===================================
+{
+  "argumentDefinitions": [],
+  "kind": "Fragment",
+  "metadata": null,
+  "name": "MyFragment",
+  "selections": [
+    {
+      "alias": null,
+      "args": null,
+      "kind": "ScalarField",
+      "name": "id",
+      "storageKey": null
+    },
+    {
+      "kind": "CatchField",
+      "field": {
+        "fragment": {
+          "kind": "InlineFragment",
+          "selections": [
+            {
+              "alias": null,
+              "args": null,
+              "kind": "ScalarField",
+              "name": "name",
+              "storageKey": null
+            }
+          ],
+          "type": null,
+          "abstractKey": null
+        },
+        "kind": "AliasedInlineFragmentSpread",
+        "name": "myAlias"
+      },
+      "to": "RESULT",
+      "path": "myAlias"
+    }
+  ],
+  "type": "Node",
+  "abstractKey": "__isNode"
+}

compiler/crates/relay-codegen/tests/catch_directive_codegen/fixtures/catch_directive_aliased_inline_fragment_no_condition.graphql

@@ -0,0 +1,6 @@
+fragment MyFragment on Node  {
+  id
+  ... @catch(to: RESULT) @alias(as: "myAlias") {
+    name
+  }
+}

compiler/crates/relay-codegen/tests/catch_directive_codegen/fixtures/catch_directive_fragment.expected

@@ -0,0 +1,32 @@
+==================================== INPUT ====================================
+fragment MyFragment on Node @catch(to: RESULT) {
+  id
+  name
+}
+==================================== OUTPUT ===================================
+{
+  "argumentDefinitions": [],
+  "kind": "Fragment",
+  "metadata": {
+    "catchTo": "RESULT"
+  },
+  "name": "MyFragment",
+  "selections": [
+    {
+      "alias": null,
+      "args": null,
+      "kind": "ScalarField",
+      "name": "id",
+      "storageKey": null
+    },
+    {
+      "alias": null,
+      "args": null,
+      "kind": "ScalarField",
+      "name": "name",
+      "storageKey": null
+    }
+  ],
+  "type": "Node",
+  "abstractKey": "__isNode"
+}

compiler/crates/relay-codegen/tests/catch_directive_codegen/fixtures/catch_directive_fragment.graphql

@@ -0,0 +1,4 @@
+fragment MyFragment on Node @catch(to: RESULT) {
+  id
+  name
+}

compiler/crates/relay-codegen/tests/catch_directive_codegen_test.rs

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<9b3e9405c461aea8f7d13327590c2c37>>
+ * @generated SignedSource<<517598dad58115fe478729b087af3fff>>
  */
 
 mod catch_directive_codegen;
@@ -19,6 +19,27 @@ async fn catch_directive() {
     test_fixture(transform_fixture, file!(), "catch_directive.graphql", "catch_directive_codegen/fixtures/catch_directive.expected", input, expected).await;
 }
 
+#[tokio::test]
+async fn catch_directive_aliased_inline_fragment() {
+    let input = include_str!("catch_directive_codegen/fixtures/catch_directive_aliased_inline_fragment.graphql");
+    let expected = include_str!("catch_directive_codegen/fixtures/catch_directive_aliased_inline_fragment.expected");
+    test_fixture(transform_fixture, file!(), "catch_directive_aliased_inline_fragment.graphql", "catch_directive_codegen/fixtures/catch_directive_aliased_inline_fragment.expected", input, expected).await;
+}
+
+#[tokio::test]
+async fn catch_directive_aliased_inline_fragment_no_condition() {
+    let input = include_str!("catch_directive_codegen/fixtures/catch_directive_aliased_inline_fragment_no_condition.graphql");
+    let expected = include_str!("catch_directive_codegen/fixtures/catch_directive_aliased_inline_fragment_no_condition.expected");
+    test_fixture(transform_fixture, file!(), "catch_directive_aliased_inline_fragment_no_condition.graphql", "catch_directive_codegen/fixtures/catch_directive_aliased_inline_fragment_no_condition.expected", input, expected).await;
+}
+
+#[tokio::test]
+async fn catch_directive_fragment() {
+    let input = include_str!("catch_directive_codegen/fixtures/catch_directive_fragment.graphql");
+    let expected = include_str!("catch_directive_codegen/fixtures/catch_directive_fragment.expected");
+    test_fixture(transform_fixture, file!(), "catch_directive_fragment.graphql", "catch_directive_codegen/fixtures/catch_directive_fragment.expected", input, expected).await;
+}
+
 #[tokio::test]
 async fn catch_directive_linked_child_has_to_result() {
     let input = include_str!("catch_directive_codegen/fixtures/catch_directive_linked_child_has_to_result.graphql");